While a small rise in ultra-processed food intake was associated with an increased risk of cancer, there was no significant link between less processed foods - such as canned vegetables, cheese and fresh bread - and cancer.

Consumption of fresh or minimally processed foods including fruits, vegetables, pulses, rice, pasta and fresh meat, was associated with a lower risk of overall cancer.

The authors said: "To our knowledge, this study is the first to investigate and highlight and increase in the risk of overall - and specifically breast - cancer associated with ultra-processed food intake."

The researchers emphasised that at this stage it was just an observational study, and no firm conclusions could be drawn about ultra-processed food consumption and risk of cancer.

Ultra-processed foods often have a higher content of total fat, saturated fat, and added sugar and salt along with a lower fibre and vitamin density.

Contaminants, some of which may be carcinogenic, have also been found in heat-treated processed food products, and many contain legal but controversial additives such as sodium nitrite and titanium oxide.

Some studies have indicated that these additives may be carcinogenic.

The researchers said the study presented several challenges, such as identifying the specific elements in ultra-processed foods that could give you cancer.